We propose to develop a suite of MEMS/microfluidic devices that will be useful for future drug delivery systems. Three projects are proposed: o In the first project, novel hydrogel/MEMS constructs will be produced. These constructs will provide a solid substrate that permits drug release rates to be modulated by a variety of signaling molecules. We will couple to MEMS substrates hydrogels whose permeability to macromolecules can be reversibly modulated by specific antigens. We will also develop new MEMS/hydrogel configurations which will expand the repertoire of this combination. 2. In the second project, a rapid microfluidic mixer will be used to produce supersaturated solutions of the antiepileptic drug, diazepam. These solutions are expected to remain stable long enough to be absorbed rapidly upon intranasal administration. The present work will test the hypothesis that the microfabicated mixer produces solutions of diazepam that will cross membranes much faster than solutions that are at phase equilibrium. 3. In the third project, a simple microfluidic device, which is expected to produce extremely uniform hydrogel microspheres, will be constructed and tested. [unreadable] [unreadable]